JSON Schema Multi-Generator

What it does

Hey hunters 👋 I'm Pasindu, the maker. Most JSON Schema generators use one sample and assume every field is required and every type fixed — almost never true for real APIs. Paste 2–5 real samples and this merges them: missing fields become optional, mixed types become nullable unions. A schema that matches reality, not one lucky response. 100% client-side, no signup, free. Part of jsondevtools.org. Feedback on the merge logic welcome — what JSON pain should I solve next?

Generate one JSON Schema from multiple JSON samples. Merging several examples detects optional and nullable fields that single-sample inference misses. Free, browser-only, draft-07 output.

Paste several JSON samples and merge them into one draft-07 schema. Fields missing from some samples become optional; fields with mixed types become nullable unions — the detail a single sample can never reveal. Add 2–5 JSON samples on the left. Click Merge into Schema . Copy the unified schema on the right. To build a JSON Schema that reflects real data, paste multiple JSON samples and merge them. A single sample marks every field as required and locks its type; merging several samples reveals which fields are optional (missing from some samples) and which are nullable (different types across samples). Everything runs in your browser — your JSON never leaves your device. Collecting a…from jsondevtools.org

• 
  Verify JSON using minimal schema2020 · github.com · ▲91

  verify-json. Contribute to yusufnb/verify-json development by creating an account on GitHub.

• 
  JSON Generator2014 · json-generator.com · ▲139

  Create mock and sample JSON using a powerful template syntax

• GJ
  Generate JSON mock data for testing/initial app development2023 · jsongenerator.io · ▲103

  Easily create complex JSON data structures using intuitive templates.

• 
  Generate React forms from JSON form schemas2015 · github.com · ▲107

  Generate, validate, and parse React forms using Mongoose-inspired JSON schemas - SteveVitali/react-form-generator

• 
  A tool to Convert JSON schemas into TypeScript Deno classes2023 · github.com · ▲43

  Hello all To preface this is just something I've been making as a learning exercise, so all feedback is appreciated. This is a tool that converts JSON schemas into TypeScript utility classes for use in Deno. Automatic Type Generation: Typescript interfaces for the compressed and uncompressed versions of your data. Compression & Decompression: Compress and decompress your data. Validation: Built-in data validation using Ajv ensures your data adheres to the schema. Reusability: Once generated, the utility classes can be used in other Deno projects. It currently only supports a subset of JSON…

• 
  JSONSchema to TypeScript compiler2017 · github.com · ▲72

  Compile JSON Schema to TypeScript type declarations - bcherny/json-schema-to-typescript

• 
  /dev/null▲486

  a social network for devs

  Dev tools · 3d ago · dev-null.sh

• 
  Whiteboard (YC W26) – an open-source IDE for thoughtful software design▲423

  open-source IDE for thoughtful software design. Contribute to devdotfast/whiteboard development by creating an account on GitHub.

  Dev tools · 28d ago · github.com

• 
  Reladraw – A diagram language where you decide where to place things▲411

  Contribute to reladraw/reladraw development by creating an account on GitHub.

  Dev tools · 26d ago · github.com

• 
  OpenBot▲362

  Grok Bot alternative: free, local, open-source, multiplayer

  Dev tools · 23d ago · openbot.run

• 
  Talanoa▲346

  Hi HN, I’m a fullstack developer, and honestly, I’ve lost count of how many side projects I’ve worked on over the years. But one idea kept coming back to me: a different kind of email client. It first came to me in 2014: “What if we could handle emails more like conversations?” Every year, I’d revisit this concept in my “Build Notes.” Ten years later, no one had built exactly what I had in mind — so I finally decided to do it myself. That’s how Talanoa was born. I wanted something focused on people, not timelines. I was tired of marking messages as unread just to remember to reply later, or…

  Dev tools · 21d ago · talanoa.email

• 
  CoreSpeed▲332

  One MCP for everything your agents need: apps, memory, tools

  Dev tools · 28d ago · corespeed.io

• 
  Fundraisly▲1,537

  AI fundraising agent that finds investors and books meetings

  AI · Jun 2026 · fundraisly.com

• 
  Homebrew 6.0.0▲1,481

  Today, I’m proud to announce Homebrew 6.0.0. The most significant changes since 5.1.0 are a new tap trust security mechanism, the new faster, smaller, default internal Homebrew JSON API, sandboxing on Linux, better defaults informed by our user survey, many brew bundle improvements, improved performance and initial support for macOS 27 (Golden Gate). Happy to discuss any questions here!

  Dev tools · Jun 2026 · brew.sh

• 
  Performative-UI – A react component library of design tropes▲1,181

  Hi HN! I was super frustrated at apps like tiktok and wechat preventing me from saving or downloading the animated gifs, so I made a little tool to turn a screen recording into a slack-sized emoji. Hope you get some value from this!

  Life & fun · Jun 2026 · vorpus.github.io

• 
  Upstream▲976

  The inbox designed for humans and agents

  AI · Jun 2026 · upstream.do

• 
  Goldfish▲958

  Press Option. It knows your work and replies like you

  AI · Jun 2026 · goldfish.sh

• 
  I made Google Trends for Hacker News by indexing 18 years of comments▲822

  Search 18 years of Hacker News and chart how any topic, tool, or person trended. Overlay terms to compare their rise and fall across 45M posts and comments.

  Life & fun · Jun 2026 · hackernewstrends.com